title: Identification of two rds/peripherin homologs in the chick retina.
abstract: OBJECTIVE
  To identify possible homologs of mammalian rds/peripherin in chick photoreceptors.
  
  
  METHODS
  An embryonic day-15 chick retinal library was screened by polymerase chain reaction with degenerate oligonucleotide primers derived from conserved segments of the mammalian retinal degeneration slow (rds) mRNA. The resultant amplification products were used to isolate cDNAs, containing complete coding regions. These clones were studied by nucleotide sequence, Northern blot, and in situ hybridization analyses.
  
  
  RESULTS
  Two new homologs of rds/peripherin were discovered: crds1 and crds2. The predicted crds1 protein is 78%, and the predicted crds2 protein is 54%, identical to mammalian rds/peripherin. The crds1 mRNA is an abundant 4.4-kb species present in photoreceptors. The crds2 mRNA is of similar size but is much rarer. No homologs of rom1 were identified in our screen. Developmentally, the crds1 mRNAs were first detectable at embryonic day 18.
  
  
  CONCLUSIONS
  Crds1 likely represents the chick ortholog of mammalian rds/peripherin, whereas crds2 is a more distant homolog. Both share an elongated C-terminal domain, an unusual feature compared with other members of the rds family.
authors.affiliation: Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas 75235-9111, USA.
authors.forename: J
authors.initials: J
authors.lastname: Weng
authors.forename: T
authors.initials: T
authors.lastname: Belecky-Adams
authors.forename: R
authors.initials: R
authors.lastname: Adler
authors.forename: G H
authors.initials: GH
authors.lastname: Travis
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D002642:Chick Embryo; D017931:DNA Primers / Q000737:chemistry; D005136:Eye Proteins / Q000032:analysis* / Q000235:genetics; D017403:In Situ Hybridization; D007381:Intermediate Filament Proteins / Q000032:analysis* / Q000235:genetics; D008562:Membrane Glycoproteins; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000032:analysis* / Q000235:genetics; D064531:Peripherins; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis; D012160:Retina / Q000737:chemistry* / Q000196:embryology; D012162:Retinal Degeneration / Q000235:genetics; D017386:Sequence Homology, Amino Acid
chemical_list: D017931:DNA Primers; D005136:Eye Proteins; D007381:Intermediate Filament Proteins; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; D064531:Peripherins; D012333:RNA, Messenger